monitor doesnt come on on boot

Sometimes when i turn on my laptop the monitor does not boot up. If i keep turning my computer off/on repeatedly it may come on but it is chance. I have tried to uninstall most recently added programmes but it is still playing up. Any suggestions would be helpful.

DO NOT plug in or unplug a monitor's video cable into / from a video port while the computer is running. Doing so can damage the monitor's circuits and/or the video adapter's circuits.

Some laptops will display on an external monitor without you having to do anything.

If you get no video on an external monitor, some laptops have a key combo that you must press to toggle the display to external video only / sometimes both / built in display video only - see the Owner's or User's manual for the model.

Thanks for your reply. I have moved the monitor back and forth whilst it is on and the LCD monitor seems to be fine so i dont think its the wiring. If the laptop does it again do you recommend plugging it in to an external monitor to see if the computer is still working? Its baffling as it sometimes turns on fine but most of the time it takes a while of turning it off and on. I have also noticed that when it does turns on, the light on the front (it looks like 3 cds on top of each other) is flashing away, but when the monitor doesnt work it does not flash. Is this the hard drive kicking in the monitor?

I put the video problems and power T shooting info in the same subject thread because either can cause no video.

If you're having a power source problem, it could be you won't get any leds coming on and no video sometimes either. E.g. if your main battery is in poor condition (e.g. the computer won't run on the battery alone) , when you have a problem with the power from the AC adapter getting into the computer, you may get no video, no leds lighting up.

Connecting an external monitor will pin down whether there's a problem with the video adapter itself - usually there's nothing wrong with it. When you do that, I'm assuming that the power led, charge led, and hard drive led are are working normally, the hard drive is spinning, etc. If there's an intermittent problem with the latter, you probably have a power source related problem.

There's also the cooling fan inside the case. On some laptops it spins while booting, then after that it only spins when the interior of the case goes above a certain temp; on other laptops it only spins when the interior of the case goes above a certain temp. In any case, you should hear it spin sometimes. If it doesn't spin at all, or if the cooling passages into and out of the case are obstructed externally (e.g. you were trying to use it while in bed with it on the sheets), or obstructed internally by too much dust and lint, the cpu (= processor) will eventually overheat, and the computer's mboard will probably eventually auto shut itself off, and it will not start up again until the temp has gone below a certain temp.

The hard drive or any data on it can't affect the video while booting before the operating system has loaded, even when the hard drive or the data on it is defective.

The hard drive can be tested with bootable diagnostics if it's the only thing that has it's led behaving oddly. Laptop hard drives then to fail sooner than desktop hard drives.

It's extremely rare for you to have a problem with the power switch, but make sure the button that presses on it is not sticking inwards, otherwise the computer will often shut off in about 4 seconds as if you had held down the button. (The behavior when you hold down the power button down is often determined by a setting in the mboard's bios - usually it's set to shut off the computer after about 4 seconds of holding it, or less often, to go instantly off, or to go into standby mode, after the button is more briefly pressed.)

On the other hand, if the laptop has ever been dropped, or if it has ever had liquid spilled on it, any of many random symptoms are possible.

Ok i have tried connecting the laptop when the monitor didnt boot up and there was no signal. I have since restarted the computer and it has come as normal. The fan is working fine its spins on boot up then calms down and kicks in when the laptop is very hot. I always use it on a tray so it has sufficient room to get air when the fan needs it.Whenever i turn the laptop on, regardless if the monitor works, the LED'S always light up but sometimes the LED that flashes when the laptop is on does not and this is when the monitor does not work.again thanks for the reply im not sure what else to try?any ideas would be greatly appreciated.

Monitors or built in displays don't boot. They either produce a display or they don't. Some will display a text message after a brief time if they are not getting a video signal - I'm assuming what you mean is the screen is black - no video at all.

Mboards boot. Operating systems load.

"..."i have tried connecting the laptop when the monitor didnt boot up and there was no signal."

Would this be a better description of what you should have said ?

"....i have tried connecting AN EXTERNAL MONITOR TO the laptop when I GOT NO VIDEO ON THE BUILT IN monitor and there was no signal. ??

If so, as I said in my previous info, you may need to press a key combo to get a display on the external monitor - see you Owner's or User's manual. .........

"....sometimes the LED that flashes when the laptop is on does not and this is when the monitor does not work."

Which monitor - the built in one ?

Which led ? If it's the hard drive activity led, it doesn't flash all the time, and if the hard drive stops working properly while it's not producing a display while it is supposed to be loading Windows, you can have nothing on the built in screen, but you should have video while booting before Windows loads in any case, unless the built in display is failing for whatever reason (there's usually nothing wrong with the video adapter). If all the other leds are working fine, the hard drive activity led never comes on even when you try doing something at that point, test the hard drive with diagnostics. (If you have a charging led, it goes off when the battery is fully charged.)For that matter, test the hard drive in any case.

BEFORE you test the hard drive, it's a very good idea to test the ram to make sure you're getting no ram errors.

If you want to try a memory diagnostic utility that takes a lot less time to run a full pass than memtest86 does, this one is pretty good - Microsoft's Windows Memory Diagnostic:http://oca.microsoft.com/en/windiag...Windows Memory Diagnostic is limited to testing only the first 4 gigabytes (GB) of RAM.It can be toggled (press T) to do a standard or a more comprehensive set of tests - use the default 6 test one first - if it passes one pass of that, use the latter one. A few of the tests in the latter set are intentionally slower.If you don't have a floppy drive, see the Quick Start Information at that Microsoft link for how to make a bootable CD of the Windows Memory Diagnostic (you need Windiag.iso - you don't necessarily need to use the program they mention to add it to the CD).

If you DO get ram errors, it's probably because the ram has a poor connection in it's slot(s). Remove the main battery, unplug the AC adapter from the laptop, remove the ram, wipe off it's contacts with a tissue or soft cloth, install the ram properly. See your Owner's or User's manual for your model if you need to know how to do that properly.

Then install the main battery, plug in the AC adapter, and try the ram test again - it should pass just fine. ......

The first things I do when troubleshooting a computer that has problems, when it does have video, is to test the ram and the hard drive.

My built in monitor is coming on black thats all. When it did it last time i connected an external monitor (TV) with no joy. I have tried to download and run a diagnostic test but again with no joy, i am not sure why?

I am really struggling with this problem and really dont know why. I am struggling with this, but appreciate your help.

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